1. Field of the Invention:
This invention pertains to apparatus by which a ladle adapted to handle molten metal may be preheated before it is placed into such service.
2. Prior Art:
Earlier ladle preheaters utilized gas or oil fired burners which gave off large quantities of unwanted gases and which were noisy in operation. In response to this problem, ladle preheaters were constructed using electrical resistance elements as sources of heat. These devices included a housing having a number of depending electrical resistance heating elements, the apparatus being placed on the upper edge of an upwardly open stationary ladle by means of a lifting device, such as a crane or hoist. In use, considerable electrical energy is needed and thus the provision of a power line necessitated that such line have sufficient flexibility and movability so as to accomodate all the movements of the preheater during its placement on and removal from the ladle. Further, the resistance elements, being rather large, are quite fragile and were frequently subjected to lateral forces during lateral movement, such as by their bumping against the ladle or any other adjacent object. It is believed that in some instances, such movable ladle preheaters required cooling water to avoid overheating of power supply lines and associated electrical components disposed remotely from the heating portions of the heating elements.